Medium-to-high voltage electric power distributing lines still use wooden poles nowadays, mainly in rural zone, city periphery and mainly in elevated regions. The advantage of the wooden poles with respect to concrete poles, in the latter case, is due to its lower weight that makes it easier the installation thereof in areas of difficult access. However, these poles are to be replaced periodically due to early deterioration primarily caused by the action of xylophagous agents, fungi and also burning that always occurs in rural areas.
An alternate sufficiently advantageous for the problems mentioned above is to cover the poles prior to installing or already installed with materials capable of performing double function: to protect the wood against xylophagous agents and against burning. One of the most versatile materials to be used as coating is epoxy resin. Epoxy resin is a low viscosity liquid material that upon reacting with another component, also referred to as hardener, becomes rigid. The epoxy resin also provides high adhesion capacity to metal and wooden substrates etc. and has high barrier property, that is, it is impervious to water and other chemical agents.
Thus, epoxy resin is a string candidate to protect wooden poles. However, the flame resistance thereof is low.
In the prior art methods for extending the service life of wooden poles are already known.
The patent document U.S. Pat. No. 5,553,438, published Sep. 10, 1996, “Methods of extending wood pole service life”, refers to extending the service life of wooden poles by forming the butt end portion thereof with slots that penetrate deeply into the wood prior to treatment of the wood with preservatives. After drying, the butt end of the pole is encased in a shell, suitably of polymers, that is bonded to the butt of the pole and presents a barrier to the penetration of fungus or insects, and likewise prevents the passage of liquids which might leach preservative from the pole into the surrounding ground.
The patent document U.S. Pat. No. 5,185,214, published Feb. 9, 1993, “One step process for imparting decay resistance and fire retardancy to wood products”, refers to a one step process for imparting both decay resistance and fire retardancy to wood and cellulosic materials by impregnating the products with a treatment solution composed of a water soluble mixture of a tertiary and quaternary ammonium preservative compound and an organic phosphate fire retardant compound. This document does not disclose nor suggest any material having the anti-flame characteristic as the intended invention.
The company American Pole & Timber, www.americanpoleandtimer.com, provides wooden treated with the patented resin 21 POLY to extend the service life of the poles reducing exposure of the wooden core. However, said resin 21 POLY is a polyurea system of plural components. Further, the application of the same occurs by means of a spraying system at high pressure and high temperature. The drawback of this resin 21 POLY is that it is a system of complex application. This resin 21 POLY does not provide anti-flame characteristic or the capacity of application on site.